That method is much too expensive for an alt-azimuth.

But a simple arrangement of belted wheels in place of the toothed wheels _a_ and _c_ might very readily be prepared by the ingenious amateur telescopist; and I feel certain that the comfort and convenience of the arrangement would amply repay him for the labour it would cost him.

My own telescope--though the large toothed-wheel and the quadrant were made inconveniently heavy (through a mistake of the workman who constructed the instrument)--worked as easily and almost as conveniently as an equatorial.
Still, it is well for the observer who wishes systematically to survey the heavens--and who can afford the expense--to obtain a well-mounted _equatorial_.

In this method of mounting, the main axis is directed to the pole of the heavens; the other axis, at right angles to the first, carries the telescope-tube.

One of the many methods adopted for mounting equatorials is that exhibited--with the omission of some minor details--in fig.9._a_ is the polar axis, _b_ is the axis (called the declination axis) which bears the telescope.